Narrow Band Imaging (NBI) has been known in the related art; in NBI, illumination light in a wavelength that is converted to a narrow band and that tends to be absorbed by hemoglobin contained in blood is radiated, and a capillary or the like at the mucosa surface is displayed with emphasis (for example, see Patent Literature 1).
It is expected that this Narrow Band Imaging will serve as an alternative observation method to dye-spraying which is widely used for detailed diagnosis of esophagus regions and pit pattern (ductal structure) observation of the large intestine, and it is also expected that NBI will contribute to realizing more efficient examination by reducing examination time and the incidence of unnecessary biopsies.